IK Handles Parented to Hip Controller
The solution to your first problem will require a look at the file. But your second one can be solved without seeing it. The most straightforward way to attach your props to your rigs is probably to create a Child Of constraint. With your prop selected in Object Mode, look for the Object Constraint tab in the Properties Panel. From the Add Object Constraint dropdown, find and select Child Of. For the Target, choose your armature. Once chosen, you have access to a new text field for choosing the bone itself within the armature that you want to become the prop's parent. You probably want to make the target the IK handle of the hand in this case. You may notice after choosing a bone in this field that the prop jumps wildly. Press Set Inverse to make it return to its original position. When you move the parent, the prop moves as well.
The reason we use a Child Of constraint instead of a direct parenting relationship (from the Set Parent To menu) is because you can't keyframe changes to direct parenting relationships. But you can keyframe a change to the influence of any constraint, by right-clicking on the Influence slider, and setting one. This allows you to turn off the effect of the constraint at will, such as in those cases where the prop is intended to be free of a character's grasp at the moment.